Screw-attached pick-up dental coping system and methods

ABSTRACT

A temporary alignment system and method for holding a dental coping to an implant abutment using the same threads in the abutment that are used for definitive attachment are disclosed. The disclosed temporary fasteners initially orient and hold a coping against an abutment with a force along the same axis as the semi-definitive screw. The aligned coping can be picked-up in a closed-tray impression process without unscrewing the temporary fastener. Embodiments include threaded posts that release copings from the abutment through axial forces. Some embodiments include a threaded post with separable cap that is picked-up with the coping. Methods for converting an existing prosthesis for screw attachment to implants in a single visit and digital capture of the converted prosthesis are described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure claims priority of U.S. provisional patent applicationNo. 62/742,942, filed on Oct. 9, 2018, and U.S. provisional patentapplication No. 62/774,402, filed on Dec. 3, 2018, and U.S. provisionalpatent application No. 62/818,082, filed on Mar. 13, 2019. All of theabove provisional applications are incorporated herein by reference intheir entirety.

COPYRIGHT NOTICE

A portion of the disclosure of this patent application contains materialthat is subject to copyright protection. The copyright owner has noobjection to the reproduction by anyone of the patent document or thepatent disclosure as it appears in the Patent and Trademark Officepatent files or records, but otherwise reserves all copyright rightswhatsoever.

BACKGROUND OF THE INVENTION

Different systems have been introduced for attaching dental prosthesesto dental implants to replace one or more natural teeth. In order tosimplify future modification or replacement needs, it is desirable tohave reversable attachment between the implants and prostheses usingmechanical systems as opposed to directly bonding these componentstogether. These systems require features to provide both properalignment and retention for acceptable use by the patient. Intermediatecomponents such as copings and separable abutments having differentlengths or orientations are often employed to provide properregistration between a dental prosthesis, one or more implants embeddedin the patient's jawbone, and the soft-tissue and any remaining naturalteeth. These intermediate elements may be mutually attached with screwsor with ball-and-socket or other forms of snap-on mounts. In the case ofa single-tooth crown attachment, the coping and abutment surfacespreferably include features to remove rotational symmetry in the matingof the abutment and coping surfaces.

Rotational locking features may also be included in these single mountsystems. When the prosthesis contains multiple copings for attachment tomultiple abutments, this rotational fixation is not generally required.For example, 30 degree tapered mating surfaces for multiple interfacelocations are sufficient to provide complete registration.

It is common to attach a complete upper or lower denture to four or moreimplants. The multi-unit abutment system interfaces with mating surfacesof the final prosthetic. In some cases, these dentures may be designedor fabricated from scratch following the pulling of undesirable teethand mounting of implants. In other cases, no teeth are pulled, but it isdesirable to convert an existing removable denture to definitivemounting to new implants. In some cases, it is preferable to convertthese existing dentures shortly after the implants are placed. Thischair-side processing decreases patient discomfort by providing at leasttemporary dentures more quickly.

Dental impressions are often used to provide information on the locationof implants, soft tissue and existing teeth for designing new prosthesesor mounting copings in existing dentures for implant attachmentconversion. Generally the copings are mounted to implant abutments andan impression is made to provide location information for the prosthesisthrough the copings. Impression material is introduced and cured aroundthe copings to define their position. In the case of transfer copings,less rigid impression material is used to form a cavity for each coping;the coping remains attached to the abutment and the cured impression isremoved. Subsequently, copings are inserted into the impression. In thecase of pick-up copings, the coping is directly retained in theimpression material after curing. That is, the copings are picked-upwhen the impression is removed from the mouth. The resulting alignmentof pick-up copings is generally superior to transfer copings as a resultof the direct transfer of coping location information. Transfer copingsintroduce an indirect secondary alignment reference since the insertionof the coping into the impression may not accurately duplicate theoriginal position, particularly in insertion depth.

Pick-up copings can be used with either an open tray or a closed trayprotocol. For snap-on systems, a closed impression tray pick-uptechnique may be done. The tray can be closed because there is no needto access the copings in order to disconnect them after the impressionmaterial sets. However, it is desirable to ensure that the assembly ofsnap-on copings can be removed without patient discomfort. The amount offorce required to remove the tray or converted prosthesis depends uponthe total number of implant abutment/coping sets and their position andmutual alignment. Some snap-on systems provide features to providedifferent retention levels, but this complicates the installationprocess. Special tools have been introduced to help separate impressiontrays or prostheses with snap-on systems, but may still result inpatient discomfort. Since snap-on systems are generally physicallylarger than dental screws, converting an existing denture may requirelarge clearance cavities to be bored into the existing denture before itcan be used as an impression tray in a pick-up coping process. Theselarge holes may significantly reduce the mechanical stability of theexisting denture. The mechanical precision required of snap-on systemelements generally makes them more expensive than screw-attachedsystems.

The simplicity of screw-attached systems provides some benefits oversnap-on systems beyond fabrication cost. The mounting pressure betweenthe coping and abutment is readily controlled through the torque appliedto the screw to tighten it. This axial tension control and theself-aligning characteristics of engaged screw threads provides morecertainty in the engagement force and relative orientation of thecomponents. Even if a screw breaks, techniques are known for removingthe pieces without damage to surrounding components. Screws also have abenefit of independence for removal since each coping can be loosenedindividually. Tilting the prosthesis after screw removal to disengageone coping cannot cause reengagement of another coping.

A disadvantage with commercially available screw-attachment systems forpick-up copings is the requirement for using an open-tray impression inorder to release the coping from the abutment after the impressionmaterial sets. By having an opening in the tray or existing denture,impression screws may be used. These impression screws extend throughthe tray beyond the impression material and can be unscrewed after thematerial sets. The impression screws use the same abutment threads asthe semi-permanent screws used to attach the prosthesis later. As aresult, the introduction of alignment uncertainty through a secondaryreference may be avoided or minimized. The copings used with theimpression screws are often relatively long and require modification fordenture conversion. This customization may result in larger clearanceholes in dentures and require additional process time by the dentalpractitioner. The length of the impression screws sticking through thetray can cause patient discomfort and a gag reflex. In the case ofdenture conversion, clearance for a set of impression screws atdifferent angles may require additional material removal leading to aweakened denture. A schematic representation of the larger through-holes136 required using conventional denture conversion processes for screwattachment are illustrated in FIGS. 93-94. The impression screws canalso prevent the patient from applying bite pressure during the pick-upprocess to ensure proper registration of the modified denture andopposing teeth.

Prosthetic dentistry has rapidly moved into the realm of digital designand manufacturing. Typically, this requires that a digital model iscreated from a physical model or impression to allow digital design andmanufacturing techniques to produce a physical prosthetic that can bedelivered to a patient for restoration of dental and oral structures.When making a dental restoration with implants in this manner, animplant impression coping is often used in the mouth to reference theposition of the implant geometry relative to surrounding structures suchas gingiva, adjacent teeth, opposing teeth, etc. Once removed from themouth, an implant analog is attached to the impression coping that waspicked-up or transferred. With the lab implant analog attached to theimpression coping in the elastomeric impression, dental stone is flowedinto the impression and allowed to harden before separation from theimpression with a resultant dental cast. A scan flag is attached to thelab analog on the dental stone model and is scanned in by laser oroptical scanning technology. The scan flag is used for design softwareto reference and replicate the accurate positioning of the virtualimplant relative to the adjacent teeth, gingiva and opposing tooth, aswell as the timing of the implant and other pertinent implantgeometries. Once the virtual implant is accurately brought into thedesign software, a prosthetic can be designed by following the workflowin the design software. A completed design is post-processed, and a CADfile is used in CAM software to direct either the 3-D printing ormilling of the designed prosthesis. The manufactured prosthesis isverified on the physical model in a remote prosthetic manufacturing labprior to delivery to the dentist or is verified directly on the dentalpatient if the prosthesis was manufactured in the local dental clinic.It is currently the standard of care to verify the fit, form, andfunction on a physical model.

Recently, an impression scan flag was introduced to the market for a fewmajor implant systems and the most common multi-unit geometry. This scanflag allows for an impression to be digitized without the creation of astone model. A digital model is created directly from the elastomericimpression, a prosthesis is designed digitally and processed with CAMsoftware and both a 3-D printed model and 3-D printed or milledprosthesis is finished and tested on the 3-D printed model. Thedisadvantage of the 3-D printed model for full arch implant prostheticsis the positioning of the implant lab analog within the 3-D printedmodel introduces a degree of inaccuracy. Additionally, an impressiononly captures the implant or multi-unit abutment relative to the tissuesand requires cumbersome steps to incorporate a provisional prosthesis orwax-up into the design software relative to the scan of the impression.

A properly converted denture provides a valuable source of informationof the relative location of the implant and its abutment surfaces,copings and soft tissue and any remaining teeth of the patient. It canbe used as a model for digital scanning to produce a duplicate dentureif needed in the future or as a starting digital model for manipulationto improve aesthetics or other characteristics. However, if themechanical integrity of the converted denture is compromised, thescanned information may not faithfully represent the relative geometryof these elements and result in a poor fit.

Other alignment systems have been proposed which use silicone or meltingscrew threads to allow closed tray transfer for definitive screwattachment, but the practicality of providing adequate alignment andseating forces with a screw diameter in the range of existing systems orovercoming the lack of disengagement independence required in meltingall threads simultaneously without patient discomfort has not beendocumented. Details on removing any residual material in the abutmentthreads or in the prosthesis after the pick-up process have not beendisclosed. Other hybrid systems that use a snap-on engagement for thepick-up coping during transfer and subsequent screw-attachment have alsobeen proposed, but detailed information on the tradeoffs in precisionand associated complexity or size required for equivalent performance toopen-tray impression screw techniques have not been disclosed. A generalneed exists for systems that improve clinical efficiency, implant toprosthesis alignment accuracy, application to a wide range of copingdesigns and sources and patient comfort over existing systems.

The present disclosure includes system and methods that address one ormore of these issues in the prior art.

BRIEF SUMMARY OF THE INVENTION

Some embodiments of the invention include a screw-in fastener systemused to temporarily retain a coping on an abutment during bonding of thecoping into a blind hole located in the tissue-side of a removabledental element such as a removable complete denture. The temporaryfastener system disclosed has features to allow easy removal of thedental prosthesis from the fastener post after pick-up of the copinginto the dental prosthesis is complete, without the need for specialtools or access to the fastener system to unscrew it.

Some embodiments include a temporary fastener with a male-threadedbottom portion that is installed into the screw threads of an abutment,and an axially separable top portion, or cap, that retains the copingonto the abutment. The separable portion allows removal of the copingpicked-up in the dental prosthesis without requiring mechanical accessto the fastener. The inventive concepts disclosed facilitate easierinstallation and removal on multiple abutments that may be oriented atdifferent compound angles when compared to the conventional open-trayprocesses and long impression screws. The temporary fastener may engagethe same screw threads of the abutment that are used to definitivelyattach the prosthesis. In this manner, the coping is held against theabutment for the pick-up process with a force oriented identically tothat of the final screw mounting. The retention of the cap on the screwpost can be designed to provide a desired force holding the coping tothe abutment through the applied torque on the temporary fastener. Thecap can be attached to the post through a combination of knownmechanical attachment means including but not limited to interferencefits, adhesives, snap fits or other elastic and inelastically deformingretention elements. The cap may also be formed as an integral part ofthe screw post that has portions that fracture as a result of an appliedaxial force. In addition to applied axial forces, the cap may separatefrom the post as a result of retention changes resulting from chemicalor thermal processes and or the application of electromagnetic energyduring or subsequent to the pick-up process.

Other embodiments include a threaded post that has a temporary retentionfeature that engages the coping without a separable cap. Theseembodiments engage the abutment threads in mounting the coping, butrelease the coping after bonding to the prosthesis.

The disclosed systems and methods can be applied to single toothprostheses with copings and abutments with orientational features or formultiple tooth prostheses using copings and abutments with symmetricalmating surfaces such as 30 degree tapers.

In some embodiments, the temporary fastener is driven into the abutmentthreads by a tool that engages the post. In other embodiments, thetemporary fastener is driven into the abutment threads by a tool thatengages the cap. The drive torque can be designed to be sufficient forholding the coping to the abutment accurately, but less than the torquethat would result in movement of the cap relative to the post.

In some embodiments, the threaded end of the post portion of thetemporary fastener has a deflecting feature that allows the post toengage or disengage the abutment threads through axial motion instead ofa rotary screw motion.

One embodiment describes a system for aligning a dental implantabutment, coping and separable dental element for definitivescrew-attachment comprising:

-   -   a temporary alignment fastener comprising:    -   a post having an axis, a first post end and second post end,        wherein the first post end is threaded for screw attachment to        the implant abutment;    -   a cap, wherein the cap is attached to the second post end;        and wherein the temporary alignment screw is configured to hold        the coping against the implant abutment when the first post end        is screwed into the implant abutment and wherein the cap is        separable from the post through a release force directed away        from the first post end.

One embodiment describes a system for aligning a separable dentalelement for installation to a threaded implant abutment with adefinitive screw having a head and threaded shaft portion comprising:

a coping having a distal end shaped to engage with the implant abutmentand a proximal end with an aperture sized to allow the shaft portion ofthe definitive screw to pass through;

a temporary screw having a distal end portion adapted to engage thethreads of the implant abutment and a proximal end portion havingtemporary engagement means for attachment adjacent to the proximal endof the coping wherein the temporary screw holds the distal end of thecoping in alignment against the implant abutment when the distal endportion of the temporary screw engages the implant abutment threads andwherein the temporary engagement means releases the coping withoutdisengaging the post portion of the temporary screw upon the applicationof a predetermined axial force in the proximal direction.

In some embodiments, an existing removable denture is converted to ascrew attached denture by milling pockets to allow copings to be bondedin a pick-up process. In this process, the denture acts in an equivalentmanner to a closed impression tray. Proper registration can be confirmedby having the patient bite down on the denture during the pick-upprocess. After coping pick-up, clearance for the definitive screws canbe drilled using the coping as a guide. The converted denture can beused with scan flags to provide a 3-dimensional digital capture. Thus adigital model can be used to make a duplicate prosthesis or as thestarting point for a new custom prosthesis.

One embodiment describes an alignment system for converting an existingdenture for screw attachment to threaded implant abutments designed toperform the process of:

-   -   mounting pick-up copings to the implant abutments with temporary        fasteners, adhering the copings to cavities formed in the        existing denture,    -   pulling the denture with secured pick-up copings away from the        implant abutments,    -   unscrewing the threaded portions of the temporary fasteners from        the implant abutments,    -   forming definitive screw clearance holes in the denture,    -   mounting the denture to the implant abutments with definitive        screws that engage the same implant abutment threads as the        temporary fasteners, wherein the unscrewing the threaded        portions of the temporary fasteners and the forming definitive        screw clearance holes in the denture may occur in either order.

For the purposes of this disclosure, a separable dental element isdefined to be anything that incorporates one or more dental copings thatcan be mounted and removed from one or more implant abutments. Differentcoping designs are known in the dental industry, and the systems andmethods disclosed here can be adapted to work with manycommercially-available types of copings including pick-up copings,temporary cylinders, inserts and impression copings. Implant abutmentsare known in the dental industry having compatible interfaces to thesecopings. Since the mechanical interface is the same, for the purposes ofthis disclosure, implant abutment is considered a generic term thatincludes abutment analogs. Description of alignment systems and processmethods with copings and implant abutments that are installed in apatient's jaw should be considered to also describe equivalent inventiveconcepts that may be used with copings and implant abutment analogs in adental lab. The inventive concepts disclosed herein can be used withdifferent types of separable dental elements. The separable dentalelement can be any form of impression used in a dental lab to assist increating and testing dental prostheses. A separable dental element canalso be a dental prosthesis fabricated in the dental lab using aphysical model made from the impression, a dental prosthesis newlyfabricated, or an existing prosthesis being converted for screwattachment. A dental prosthesis is defined to include a single-toothappliance such as a crown, or any multiple-tooth bridge or denture.These prostheses may incorporate copings to provide a separableinterface to provide orientation with an appropriate abutment attachedto a patient's jaw or gingiva. The abutments for use with the inventiveconcepts disclosed herein include screw threads to mount the prosthesiswith copings onto the abutments. While the concepts describe femalethreads in the abutment mating with male threads on a mounting screw,this is for convenience in disclosure. The inventive concepts could beapplied with systems having male threads in the abutment engaging ascrew with female threads for mounting the prosthesis. These areconsidered to be straightforward variations of the inventive concepts.

For the purposes of this disclosure, the abutments may be integral tothe implants embedded into the patients jaw or gingiva, or they may beseparate units that are attached to the implants. The inventive conceptsdisclosed apply to both configurations.

For the purposes of this disclosure, an existing denture should beinterpreted broadly to include any prosthesis that has been createdprior to the use of the innovative systems and methods disclosed. Anexisting denture may be a loose denture that was worn by the patientprior to the installation of implants were installed, or it may be a newdenture that is in the process of first fitting in the patient's mouth.

The systems and methods disclosed herein can be used with prostheses forattachment to both the upper and lower jaw. As a result, portions of thesystem that are oriented downward for the lower jaw will be orientedupward for the upper jaw and vice versa. For convenience, a disclosureof an embodiment of inventive concepts that is limited to a single jaworientation, is considered to disclose an embodiment for the oppositejaw orientation. When referring to the perspective of a clinician,proximal portions are nearer to the clinician than distal portions.While a term such as top is the opposite of the term bottom, andproximal is the opposite of distal, their actual relative orientationwill be determined by the context of their use. The term tissue-side isused interchangeably with intaglio to indicate the side of a prosthesisthat is opposite the occlusal or cameo surface.

The inventive systems disclosed are beneficially applicable toscrew-attached prostheses. Key benefits of screw-attachment are variabletightening torques and reversibility. The terms permanent,semi-permanent, definitive and final when referring to screw-attachmentare used interchangeably in this disclosure. A conventional screw thatis definitively attached can still be removed by accessing the screw androtating it in the opposite direction that was used for attachment. Forthe purposes of screw-attached prostheses for this disclosure, theattachment is semi-permanent, permanent or definitive in the sense thatfrequent attachment and removal is not anticipated for normal use. Incontrast, the temporary screw attachment is applied for a plannedprocess duration or other anticipated interval. Removal of asemi-permanent or definitive screw is generally motivated by a problemor an opportunity for an improvement. Access to the screw to apply atool for removal may require removal of material covering the screw foraesthetic reasons.

Other terms in the specification and claims of this application shouldbe interpreted using generally accepted, common meanings qualified byany contextual language where they are used. The terms “a” or “an”, asused herein, are defined as one or as more than one. The term“plurality”, as used herein, is defined as two or as more than two. Theterm “another”, as used herein, is defined as at least a second or more.The terms “including” and/or “having”, as used herein, are defined ascomprising (i.e., open language). The term “coupled”, as used herein, isdefined as connected, although not necessarily directly, and notnecessarily mechanically. The terms “about” and “essentially” mean±10percent. Reference throughout this document to “one embodiment”,“certain embodiments”, and “an embodiment” or similar terms means that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment of thepresent invention. Thus, the appearances of such phrases or in variousplaces throughout this specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments without limitation. The term “or” as used hereinis to be interpreted as an inclusive or meaning any one or anycombination. Therefore, “A, B or C” means any of the following: “A; B;C; A and B; A and C; B and C; A, B and C”. An exception to thisdefinition will occur only when a combination of elements, functions,steps or acts are in some way inherently mutually exclusive.

The drawings featured in the figures are for the purpose of illustratingcertain convenient embodiments of the present invention and are not tobe considered as limitation thereto. The term “means” preceding apresent participle of an operation indicates a desired function forwhich there is one or more embodiments, i.e., one or more methods,devices, or apparatuses for achieving the desired function and that oneskilled in the art could select from these or their equivalent in viewof the disclosure herein and use of the term “means” is not intended tobe limiting. Other objects, features, embodiments and/or advantages ofthe invention will be apparent from the following specification taken inconjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top exploded isometric view of a first embodiment of asystem for aligning a dental implant abutment, coping and prosthesis fordefinitive screw-attachment.

FIG. 2 is a side plan view of a first embodiment of a system foraligning a dental implant abutment, coping and prothesis for definitivescrew-attachment.

FIG. 3 is a top plan view of a first embodiment of a system for aligninga dental implant abutment, coping and prosthesis for definitivescrew-attachment.

FIG. 4 is a side cross-sectional view of the system for aligning adental implant abutment, coping and prosthesis for definitivescrew-attachment along the line indicated in FIG. 3.

FIG. 5 is a side cross-sectional view of the embodiment of FIG. 4attached to the jaw and prosthesis prior to the pick-up process.

FIG. 6 is a side cross-sectional view of the embodiment of FIG. 5 afterthe pick-up process.

FIG. 7 is a side cross-sectional view of the embodiment of FIG. 6showing a drill bit creating a pilot hole for a definitive screw.

FIG. 8 is a side cross-sectional view of the embodiment of FIG. 7showing a stepped drill bit creating a clearance for the head and shaftof a definitive screw.

FIG. 9 is side cross-sectional view of the embodiment of FIG. 8 showingthe definitive screw holding the prosthesis to the implant.

FIG. 10 is an exploded top isometric view of a second embodiment of asystem for aligning a dental implant abutment, coping and prothesis fordefinitive screw-attachment illustrating a single abutment and atemporary screw with breakaway tool.

FIG. 11 is an exploded side isometric view of the second embodiment ofFIG. 10 prior to installation to the implant abutment.

FIG. 12 is an exploded side isometric view of the embodiment of FIG. 10with the breakaway tool pushed onto the post and the coping placed onthe implant abutment.

FIG. 13 is an exploded side isometric view of the embodiment of FIG. 10schematically showing the tool being rotated to screw the post into theimplant abutment.

FIG. 14 is an exploded side isometric view of the embodiment of FIG. 10schematically showing the tool breaking away from the cap after thecoping is secured on the abutment.

FIG. 15 is an exploded side isometric view of the embodiment of FIG. 10schematically showing the prosthesis being marked for positioning aclearance hole.

FIG. 16 is a side isometric view of the marked prosthesis from FIG. 15.

FIG. 17 is a side isometric view of the marked prosthesis from FIG. 16with blind clearance hole and boring tool.

FIG. 18 is an exploded side isometric view of the prepared embodiment ofFIG. 17 as adhesive is schematically applied to the coping fixed to theabutment with the temporary screw.

FIG. 19 is a side view of the prosthesis in position for curing of theadhesive applied in FIG. 18.

FIG. 20 is a bottom side isometric exploded view of the copingincorporated in FIG. 19 being picked up as the prosthesis is removedfrom the implant abutment.

FIG. 21 is a top side isometric view schematically showing the post ofthe temporary screw being unscrewed from the implant abutment.

FIG. 22 is a top side isometric view of the implant abutment preparedfor attachment of a prosthesis with a definitive screw.

FIG. 23 is a bottom isometric view of the prosthesis with picked-upcoping from FIG. 20 being drilled from the bottom to provide clearancefor the threaded shaft of a definitive screw following coping pick-up.

FIG. 24 is a top isometric view of the prosthesis with picked-up copingfrom FIG. 20 with a drill applied from the top to provide clearance forthe definitive screw head.

FIG. 25 is top exploded isometric view of the prepared prosthesis fromFIG. 24 with the definitive screw.

FIG. 26 is a top isometric view of the prepared prosthesis from FIG. 24after attachment to the implant abutment with the definitive screw.

FIG. 27 is a schematic description of a process for aligning dentalimplant abutments, copings and a prosthesis for definitivescrew-attachment.

FIG. 28 is an exploded bottom isometric view of a third embodiment of asystem for aligning a dental implant abutment, coping and prosthesis fordefinitive screw-attachment with tool oriented for assembly.

FIG. 29 is an assembled bottom isometric view of the embodiment of FIG.28 with temporary screw and coping inserted into tool.

FIG. 30 is a side view of the system of FIG. 29 after assembly with theimplant abutment.

FIG. 31 is a cross-sectional view of the assembly of FIG. 30 along C-C.

FIG. 32 is a side view of the assembly of FIG. 28 after the pick-upprocess showing the removal end of the tool engaging the retainedtemporary screw post.

FIG. 33 is a cross-sectional of the assembly of FIG. 32 along D-D.

FIG. 34 is an exploded isometric view of another embodiment of atemporary screw of a system for aligning a dental implant abutment,coping and prosthesis for definitive screw-attachment.

FIG. 35 is an isometric view of the temporary screw of FIG. 34 from thescrew thread end.

FIG. 36 is an isometric view of the temporary screw of FIG. 34 from thecap end.

FIG. 37 is a bottom isometric view of a jaw with multiple abutments inpreparation of marking a prosthesis as part of the process for aligninga dental implant abutment, coping and prosthesis for definitivescrew-attachment.

FIG. 38 is a top isometric view of the prosthesis of FIG. 37 showingabutment location markings.

FIG. 39 is a top isometric view of the prosthesis with clearances milledto receive copings for pick-up.

FIG. 40 is a bottom isometric view showing installed copings and theassembly of a coping to an implant abutment with a temporary screw andtorque driver.

FIG. 41 is a top isometric view showing adhesive being dispensed inrecesses of the prosthesis.

FIG. 42 is a bottom isometric view of the abutments with attachedcopings in the process of being positioned into the recesses of theprothesis after adhesive is dispensed.

FIG. 43 is a top isometric view of the copings attached to theprosthesis after adhesive curing and pick-up.

FIG. 44 is a bottom isometric view showing the removal of temporaryscrew posts from the implant abutments after the pick-up process.

FIG. 45 is a top view of a drill in position to create a pilot hole inthe prosthesis of FIG. 43.

FIG. 46 is bottom view showing the pilot holes from the process of FIG.45 extending through the prosthesis to exit on the occlusion side.

FIG. 47 is a bottom isometric view showing a counterbore positioned onthe occlusion side of the prosthesis to provide clearance for thedefinitive screw.

FIG. 48 is a bottom isometric view illustrating a reamer positioned toclean residue from the bore.

FIG. 49 is a bottom isometric view of the prepared prosthesis withdefinitive mounting screws prior to fastening to the abutments.

FIG. 50 is a top isometric view corresponding to FIG. 49.

FIG. 51 is a top isometric view of an embodiment of a component suitablefor use as a scan flag for digital capture and a laboratory analog forphysical model creation.

FIG. 52 is a bottom isometric view of the component from FIG. 51.

FIG. 53 is a bottom isometric view showing the component of FIG. 51positioned for screw attachment to the converted prosthesis of FIG. 49.

FIG. 54 is a top isometric view of FIG. 53.

FIG. 55 is a top isometric view showing the assembly of FIG. 54 mountedon a stand in preparation for scanning.

FIG. 56 is a side view of FIG. 55.

FIG. 57 is an isometric view of the assembly of FIG. 54 with reinforcingbars mounted prior to pouring of dental stone.

FIG. 58 is a schematic flow chart illustrating options for creating andattaching a permanent prosthesis.

FIG. 59 is an exploded isometric view of the torque driver shown in FIG.40.

FIG. 60 is top isometric view of the torque driver of FIG. 59 partiallyassembled.

FIG. 61 is a top isometric view of the post removal tool shown in FIG.44.

FIG. 62 is a top isometric view of an embodiment of a temporary screwsimilar to FIG. 1 schematically illustrating axial motion of the capaway from the post threads from screwing after the coping contacts theabutment.

FIG. 63 is a top isometric view of the embodiment of FIG. 62 in whichthe temporary screw post end has become flush with the top of the cap.

FIG. 64 is a top isometric view of a temporary screw post embodimenthaving a cylindrical stem.

FIG. 65 is a top isometric view of a split temporary screw postembodiment having deflecting sections.

FIG. 66 is an isometric view of a temporary screw post embodiment havingsymmetric axial splines.

FIG. 67 is an isometric view of a temporary screw post embodiment havinga weakened portion facilitating lateral movement during pick-up.

FIG. 68 is a bottom isometric view of a temporary screw embodimenthaving a spring cap.

FIG. 69 is a bottom isometric view of a one-piece temporary screwembodiment designed to fracture under axial loading.

FIG. 70 is a cross-sectional view of a temporary screw embodimentincorporating a rounded interface between cap and post facilitatingpivotal movement as illustrated.

FIG. 71 is a cross-sectional view of a temporary screw embodimentincorporating a restricted interface between cap and post facilitatingpivotal movement and protective film.

FIG. 72 is a cross-sectional view of a temporary screw embodimentincorporating a spring cap with preferential axial movement in thepick-up direction.

FIG. 73 is a cross-sectional view of a temporary screw embodimentincorporating a laminar cap fixed to the end of the post.

FIG. 74 is a cross-sectional view of a temporary screw embodimentincorporating a compliant interface between the cap and post.

FIG. 75 is a cross-sectional view of a temporary screw embodimentincorporating a split post that has deflecting sections with screwthreads shaped to facilitate axial separation without unscrewing thepost threads.

FIG. 76 is a cross-sectional view of a temporary screw embodimentincorporating an interface material between the cap and post.

FIG. 77 is a cross-sectional view of a temporary screw embodimentincorporating an O-ring interface between the cap and post.

FIG. 78 is a cross-sectional view of a temporary screw embodimentincorporating a cup-shaped interface material between the cap and post.

FIG. 79 is a bottom isometric view of a temporary screw embodimentincorporating a split collar cap.

FIG. 80 is a top isometric view of a temporary screw embodimentincorporating a planar spring that flexes when pulled perpendicular tothe diameter indicated.

FIG. 81 is a top isometric view of a temporary screw embodimentincorporating a planar spring that flexes when pulled parallelperpendicular to the diameter indicated.

FIG. 82 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which the coping is held bymechanical interference to the proximal end of the threaded post.

FIG. 83 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which the coping has spring fingersholding the proximal end of the threaded post.

FIG. 84 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which the coping has collet-typespring fingers holding the proximal end of the threaded post.

FIG. 84A is a top view of the embodiment of FIG. 84.

FIG. 85 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which the proximal end of threadedpost has a slotted spring section holding the coping.

FIG. 86 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which a compressed ring holds thecoping to the proximal end of the threaded post.

FIG. 87 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which a compressed ring with au-shaped cross-section holds the coping to the proximal end of thethreaded post.

FIG. 88 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which a thin cap fixes the coping tothe proximal end of the threaded post.

FIG. 89 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment in which a filler material is placed inthe bore of the coping at the proximal end of the threaded post.

FIG. 90 is a cross-sectional view of an embodiment of a system foraligning a dental implant abutment, coping and prosthesis forsemi-permanent screw-attachment showing a tool engaging features of thecoping to screw in the threaded portion of the post.

FIG. 91 is a bottom isometric view schematically illustrating thematerial removed from an existing denture necessary with inventiveconcepts disclosed in preparation for pick-up.

FIG. 92 is a top isometric view schematically illustrating the materialremoved from an existing denture necessary with inventive conceptsdisclosed in preparation for pick-up.

FIG. 93 is a bottom isometric view schematically illustrating thematerial removed from an existing denture necessary using prior artimpression screw systems.

FIG. 94 is a top isometric view schematically illustrating the materialremoved from an existing denture necessary using prior art impressionscrew systems.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an exploded view of one embodiment of a temporary alignmentsystem 12 for use in a direct coping pick-up process for screwattachment of a prosthesis. Implant abutment 8 has a distal end whichmay include attachment feature portion 135 illustrated as a screw threadfor direct attachment to the patient's jaw and a proximal end with anabutment shaped to accommodate a coping 9. The abutment includesthreaded section 18. The coping has a central bore 16 to accommodatescrew fastening and may include ridges 17 or other structures or surfacetreatments to increase retention to the prosthesis with adhesive. Thecoping and abutment mating surfaces as shown in FIG. 1 are symmetrical.The inventive concepts of this disclosure may also be applied toabutment and coping systems that are keyed to restrict matingorientation. The coping may be mounted onto the abutment throughrotation of a temporary adjustment screw comprising a threaded post 10and cap 11. The cap 11 is mechanically attached to post 10 in a mannerthat allows relative axial motion with the application of apredetermined force. As illustrated in FIG. 1, cap 11 has a squarecentral bore 13 that is press-fit onto a square portion 14 of post 10.The cap 11 temporarily retains coping 9 onto implant abutment 8 duringthe pick-up process of the coping into the prosthesis with a forcealigned directly along the same axis as the semi-permanent screw thatwill be used for definitive prosthesis mounting. The portion of the postengaging the abutment threads also prevents any pick-up material fromcontacting the abutment screw threads. After the coping is picked-upinto the prosthesis, the cap and coping may be released from theabutment by applying an axial force. In the embodiment shown, the postthreads 15 remain engaged with abutment threads 18 after the pick-upprocess. The post can then be removed from the abutment by unscrewingit. The prosthesis with embedded coping can be subsequently processed toaccommodate semi-permanent screw attachment as will be described later.

FIGS. 2 and 3 show a side and top view of the assembled system of FIG.1; FIG. 4 shows a cross-sectional view along the axis as indicated. Asshown in FIG. 4, matching conical surfaces on the exterior of theimplant abutment 8 and the interior of the coping 9 are engaged. Thecoping is pulled into alignment by an axial force from the lower surfaceof the cap 11 pushing against the upper surface of the coping fromscrewing the threads of post 10 into the implant abutment. The distalend of the abutment may be directly attached to the patient's jaw orattached to a separate implant attached to the jaw. The inventiveconcepts are not dependent upon the nature of the implant, so the distalend attachment feature 135 is represented schematically.

The capability for relative axial movement between the cap 11 andtemporary attachment post 10 allows separation of the temporaryattachment post from the cap without tools after retaining the copingonto the abutment during fitting and bonding of the coping into theprosthesis. These parts are accurately aligned during the bondingprocess since the temporary post engages the abutment threads to providean axial force holding the coping to the abutment just like the screwused for final attachment.

The cap may be sized to have an amount of press-fit mechanicalinterference to the temporary attachment post to provide an axialretention force of approximately 20 to 900 grams, this force beingsufficient to retain coping 9 during assembly while allowing relativelyeasy pickup removal of the coping and prosthesis from the temporaryattachment post after assembly. The temporary attachment post 10 mayinclude indicators (not shown) in the end by the cap 11 to provideintermediate visual and/or tactile feedback on the depth of threadedengagement of the post during screw attachment of the coping to theabutment.

In this embodiment, screw driving torque is provided by the squarecross-section of the cap aperture and temporary attachment post. In thecross-sectional view of FIG. 4, the post 10 has been screwed in so thatonly a small beveled surface of the post extends above the top of thecap when the post threads bottom out in the abutment. Duringinstallation, this optional configuration provides feedback to thedental practitioner when the torque increases as the threads bottom. Thesquare drive tool engagement can also be designed to disengage at apre-designed minimum extension of the square post above the top of thecap. Alternatively, a tool with a specified maximum torque may be usedto ensure engagement of the coping and abutment surfaces.

The screw driving torque function may be accomplished by engaging otherfeatures on the temporary attachment post such as hex or spline orasymmetric features.

Alternately, the cap may be used to engage a screwdriver or other toolfor torqueing. For example, in the case of a cylindrical temporaryattachment post top portion, driving torque can be provided by thefriction of the press-fit between the cap and temporary attachment post.For example, a medium press-fit of a 3 mm diameter 1 mm thick nylon caponto a 1.3 mm diameter stainless steel cylindrical rod may produceapproximately 500 grams of axial retention force and 17 gram-cm drivingtorque. A typical screw thread size for appliances is m1.4×0.3. Theretention/axial force of the cap to the temporary attachment post may bedetermined by the degree of press-fit and frictional properties betweenthe cap and temporary attachment post, and/or spring featuresincorporated into the temporary attachment post and/or cap.

In actual trial installations, polymer caps of approximately 1.2 mmthickness press fit onto posts of approximately 1.4 mm diameter withcylindrical axial bores have been sufficient for installation andpick-up removal of a single prosthesis from multiple implant abutmentsin which the axes of the screw threads in the implant abutments are notmutually parallel.

The separable mechanical attachment means may include any combination oftechniques, including frictional forces from interference, adhesives,waxes, chemical bonding, solders, elastically or inelasticallydeformable spring, snap or interlocking structures, thermally orelectromagnetically fusible materials, fracturing structures, etc.

FIG. 5 through FIG. 9 show example cross-sectional views of some of thedifferent stages of installation of the temporary fastener system into adenture. FIG. 5 shows a cross-sectional view of the assembly of thefirst embodiment during the initial phase of the coping pick-up process.As illustrated, the implant abutment 8 is attached to a schematicimplant 70. The implant 70 has an interface 7 (shown schematically) thatis attached to the patient's jawbone 22. The coping 9 is held againstthe implant abutment 8 through the temporary screw comprising the post10 and cap 11. A blind clearance hole 5 in the prosthesis 3 is sized toaccommodate the coping and temporary screw. Pick-up material 71 ispositioned in the clearance hole 5 to capture the coping in properalignment within the prosthesis. After the pick-up material has set up,the prosthesis 3, coping 9 and temporary screw cap 10 assembly is pulledoff the patient's jaw as shown by the arrows in FIG. 6. The coping 9 andcap 11 are released from the implant abutment 8 and post 10, while thethreads of the post 10 keep it engaged in the implant abutment 8. Thepost 10 is subsequently removed to make the abutment threads 18available for holding the prosthesis in proper alignment with adefinitive screw.

The prosthesis/coping assembly must be processed after the pick-upprocess for screw attachment. A pilot hole is drilled with bit 72 fromthe bottom side of the assembly. As shown in FIG. 7, the diameter of thebit may be selected to use the interior bores of the coping and cap toact as guides for hand processing. Alternately, a drill guide may beemployed that engages a portion of the interior of the coping may beused to align the pilot hole. The pilot hole provides guidance for atool to provide clearance for the definitive screw shaft and head. FIG.8 shows a stepped drill 73 that cuts both clearances in a singleprocess. Alternatively, the shaft and head clearance may be drilled withtwo drills in two process steps. If desired, the cap 11 of the temporaryscrew can be fabricated of a material that is easier to drill than thecoping material to provide feedback on the drill position. It has beenfound that it is possible to distinguish where the drill is positionedby feel at the interfaces between the pick-up adhesive and the top ofthe cap (as shown in FIG. 8) and the bottom of the cap and the top ofthe coping. Since pick-up material was blocked from entering the coping,drilling resistance decreases rapidly upon breaking through the bottomof the cap and entering the interior channel of the coping. Colordifferences in the materials can also be detected. Alternatively, a toolcan be configured to fit within the bore of the coping to limit thedepth of the drill.

Once clearance for the definitive screw has been made from the top ofthe prosthesis, the prosthesis is ready for mounting to the implant withdefinitive screw 75 as shown in FIG. 9. The screw clearance hole in theprosthesis may be filled with Teflon tape and color-matching compositematerials for aesthetic purposes. In the illustrated embodiment, thecoping bore has a shoulder to engage a flat surface on the underside ofhead of the screw. Alternate configurations are possible withoutdeviating from the temporary screw system for coping pick-up disclosed.

FIG. 10 is another exploded isometric view of parts of an embodiment ofthe invention. In this example, cap 11 is integrated into a breakawayinstallation tool 18. The tool portion 19 may be used to install thetemporary attachment post 10, and then section 19 broken away atmechanically weak separation feature 20, for example, when the postbottoms out in the abutment leaving the cap portion 11 in position.Alternatively, the tool can be designed to increase stress on theseparation feature as the top of the post moves axially down relative tothe weakened section. As illustrated, after the cap portion 11 breaksaway from the tool portion 19, drive feature 21 in the tool portion maybe used to remove the post 10 after the pick-up process. One or bothends of the tool may be shaped to subsequently engage and remove thetemporary attachment post 10 after installation of coping 9 into thedenture.

FIGS. 11-26 provide schematic isometric views of the process steps forusing the elements of an exemplary embodiment introduced in FIG. 10 fora single implant system such as a crown. In FIG. 11, a schematicisometric view of a portion of the patient's jaw 22 is shown with animplant 70 (not shown) installed, and implant abutment 8 installed intothe implant. The coping 9 is placed onto the implant abutment 8, the topportion of temporary attachment post 10 is assembled onto cap 11. Thetop portion of temporary attachment post 10 and cap 11 are configuredsuch that there is a means to drive the temporary attachment post intothe abutment, while allowing axial movement of the cap 11 relative tothe temporary attachment post axis, the cap/temporary attachment postinterface having sufficient retention force to keep the coping in placeon the abutment during subsequent installation steps, and the temporaryattachment post being removable after picking up the coping into theprosthesis. Cap 11 may be attached to a break-away installation/removaltool 18.

FIG. 12 shows the coping 9 placed on the implant abutment 8 and thecap/tool 18 installed onto temporary attachment post 10. Thecoping-abutment surfaces may comprise a conical or spherical concavefeature on the coping 9 that mates with a complementary feature on thetop of the implant abutment 8, as illustrated. Alternatively, keyingfeatures may be employed to restrict relative rotational orientation,particularly in the case of single implants.

FIG. 13 shows the temporary attachment post being threaded into theimplant abutment 8, through a clearance hole in the coping 9. The capabuts the coping to secure the coping to the abutment. The cap 11 isfree to move axially along the temporary attachment post with africtional retaining force of the cap to the temporary attachment post.A known amount of retention force of the coping to the abutment isprovided by the design and materials used in the cap and temporaryattachment post.

FIG. 14 shows the tool portion of the cap being removed after the caphas broken away; the tool may be used for removal of the temporaryattachment post at a later step.

FIG. 15 shows marking of the position of the coping onto the appliancefor drilling a recess for the coping in the prosthesis.

FIG. 16 shows the prosthesis with coping drilling location marking 23.

FIG. 17 shows the prosthesis after boring the cavity for the coping; thecavity for the coping may be accurately drilled slightly larger than thecoping, without significant unwanted material removal from theprosthesis.

FIG. 18 shows pick-up material being applied to the coping and/orprosthesis after confirmation of freedom to provide proper occlusionduring dry testing. Although not illustrated, the cavity of theprosthesis or the coping may optionally include features to provideventing of excess pick-up material if desired.

FIG. 19 shows the bonded coping being picked up into the prosthesis

FIG. 20 shows the prosthesis removed from the temporary attachment post;the temporary attachment post/cap design allows removal of theprosthesis from the temporary attachment post. The coping is nowincorporated into the prosthesis.

FIG. 21 shows the temporary attachment post being removed with the toolportion of the cap.

FIG. 22 shows the abutment installed in the implant with the temporaryattachment post removed.

FIG. 23 shows drilling a small guide-hole (for example 1-2 mm diameter),through the clearance hole of the coping, into and through theprosthesis. This guide hole provides a small reference hole forenlargement of the hole to accommodate the prosthesis retaining screw.

FIG. 24 shows enlarging the guide hole to a clearance hole forprosthesis retaining screw, approximately the diameter of the head ofthe retaining screw (e.g. 1.5-2.5 mm). The clearance hole wouldtypically be drilled down to the top surface of the coping.

FIG. 25 shows the prosthesis being installed onto the implant abutmentby placing the prosthesis coping onto the abutment, and installing theprosthesis retaining screw.

FIG. 26 shows the assembled prosthesis on the implant.

FIG. 27 contains a summary of a generalized process extending the basicprocess described above for a prosthesis attached to multiple implantabutments.

Another embodiment of a prosthesis and implant alignment system and toolare shown in FIG. 28. In this case, the cap is in the form of a hex nut63 that is press fit onto alignment post 62 to act as the temporaryalignment screw. The drive tool 64 includes a concave hex socket 68 thatfits temporary post nut 63, and coping retaining portion 69 that retainscoping 61 with a slight interference fit. Thus, as shown in FIG. 29, thetemporary screw comprising nut 63 with post 62 is engaged with thesocket portion of the tool, and the coping 61 is retained in the tool.The coping is seated onto the abutment 60 by using the hex portion ofthe driver to rotate the nut and engage the threads 66 on the temporaryscrew post 62. FIGS. 30 and 31 show an exterior and cross-sectional viewof the mounting of the coping on the abutment with the tool. The toolmay also have an integrated feature for removing the post as shown inFIG. 32. For example, FIG. 33 shows a tapering feature 172 on the narrowend of tool 64 which may be used to unscrew the post. FIG. 28illustrates optional undercut 67 for stronger adhesive locking. Optionalanti-rotation flat 65 is shown. Such an anti-rotation flat may be usedon mating surfaces in circumstances in which there is a preferredorientation around the axis of the screw threads.

Another embodiment of the inventive concepts in which the cap of thetemporary screw is shaped to engage the driving tool is shown in FIGS.34-36. Cap 102 is mechanically attached to alignment post 101 at endportion 101A to form temporary alignment screw 100. This mechanicalattachment may result from press-fitting a polymeric cap 102 onto ametal post 101 to provide adequate resistance to rotary slip totemporarily attach the coping to the implant abutment while stillallowing relative axial movement during the pick-up process. Ahexalobular internal (Torx) drive feature is shown in the end of the cap102, although other bit socket shapes are possible. As previouslydiscussed, other mechanical engagement means besides an interference fitare possible. The post may be made of different materials than these, oreven be of unitary construction with weakened sections that fractureunder a desired pick-up axial force.

In a preferred embodiment the post 101 is made from stainless-steel ortitanium, and the cap of polymer such as PEEK or acetal. The shortlength of the post and threaded fastener in this embodiment allowsseparation at high degrees of angularity of the assembled parts in use.This tolerance for off-axial removal has been found to be particularlyadvantageous when the prosthesis is to be definitively screw mounted tomultiple implant abutments. Testing has verified cap axial releaseforces of up to about 5 pounds and the application of torque to the capof about 1.6 inch-ounces without slipping.

The general process for converting an existing removable denture fordefinitive screw attachment onto four implants with this embodiment isillustrated in FIGS. 37-50. This prosthesis may be, for example, aremovable denture that was used prior to implant surgery or a duplicateof such an existing denture as described in U.S. Provisional PatentApplication 62/774,402 incorporated herein in its entirety.

FIG. 37 shows a schematic representation of a human jaw portion 106 withimplant abutments 107 installed. It does not matter for this discussionif the abutments are separable from the implanted portion of the implantor not. Prosthesis 103 is shown with occlusion side 104 and intaglioside 105. Pick-up marking caps 108 are installed onto implant abutments107. The location of implant abutments 107 is marked onto the prosthesisusing customary methods by mating the prosthesis with the abutments.FIG. 38 shows the abutment positions 109 marked onto prosthesis 103.FIG. 39 shows boring of blind holes 110 slightly larger than copings 112in marked locations, with burr tool 111.

FIG. 40 shows the installation of copings 112 onto abutments 107 usingseparable fastener assembly 100, and torque driver 113 (described inmore detail later). The torque driver 113 prevents over-tightening oftemporary screw 100 and possible separation of the cap 102 from the post101 due to rotary motion. The cap 102 and/or post 101A of the separablefastener 100 may be mechanically captured or adhered to the coping 112,or may be designed to loosely fit into the bore of the coping asillustrated with axial force from tightening the separable fastenerholding the coping to the abutment 107. The prosthesis is placed overthe mounted copings to ensure proper fit.

FIG. 41 shows application of acrylic or other adhesive 114 with adhesivedispenser 144 into cavities 110 of prosthesis 103, which is subsequentlyfitted onto copings 112.

FIG. 42 shows prosthesis 103 being mated with copings 112. After theadhesive sets, the separable fasteners allow easy removal of theprosthesis from the abutments with the copings incorporated into theprosthesis. The angular tolerance for removing the prosthesis frommultiple abutments allows applying pick-up forces sequentially aroundthe edge of the prosthesis to work the caps 102 off the posts 101. Thecaps 102 remain in the prosthesis with the copings 112, while the posts101 remain in the abutments.

FIG. 43 shows the prosthesis with incorporated copings 112 after thepick-up process.

FIG. 44 shows the removal of the threaded post 101 from the implantabutment with removal tool 115. This allows the implant abutment threadsto be accessible for subsequent definitive screw attachment.

FIG. 45 shows the drilling of the small pilot hole 117 (e.g. using adrill bit 116 of approximately 1.4 mm diameter), from the intaglio side105 of the prosthesis out through the occlusion side 104. It has beenfound that the bore of the coping 112 and the bore of the cap provideadequate guidance for this hole, although a tooling guide could readilybe designed to mate with the particular coping used. The pilot hole isdrilled completely through the prosthesis to the occlusion side 104 asshown in FIG. 46.

FIG. 47 shows enlarging of the pilot hole 117 to allow clearance for aprosthetic mounting screw 121. The clearance holes 119 are drilled downto the top of the coping using counterbore drill 118. This requires onlya small diameter enlargement (for example, approximately 2.4 mm).

FIG. 48 shows a step of a final hand reaming with reamer 120 of thecoping bore to clean out any debris or remaining material from the capthat would interfere with the definitive screw.

FIGS. 49 and 50 show the final installation of prosthesis 103 ontoabutments 107 using definitive prosthetic screws 121. The screw holesmay be subsequently filled to use the modified prosthesis depending uponthe anticipated use as a short-term or more permanent prosthesis. Thissequence of process steps essentially follows the material provided inFIG. 27.

Note that in the above procedure very little material is removed fromthe prosthesis during the coping pick-up installation process. Theboring process in FIG. 39 need only be sufficient to provide clearancefor the coping and temporary screw. Angular variation in the axes of theimplant abutments does not appreciably increase the size of the cavityboring required in this closed tray process compared to the additionalprosthesis material that must be removed with relatively long impressionscrews and sleeves in a conventional open tray conversion process fordefinitive screw attachment. FIGS. 91-92 provide a schematic comparisonof the size of the recess borings required using the concepts disclosedcompared to the prior art conversion process with larger through holesin FIGS. 93-94.

The converted prosthesis with copings and screw-access channels may alsobe used as an accurate digital scan model of abutment positioning forcreating a new prosthesis. In this embodiment, dual purpose scan flagand lab analogs 122 shown in FIGS. 51-52 may be fastened to theprovisional or duplicate prosthesis 103, for example, after theclearance hole cleaning shown in FIG. 48. Features that may be presenton the scan-flag/analog include a scan-flag reference portion 123 nearthe top of the analog, reference scan-flag features such as flats 124,axial and radial retention feature 128, screw attachment 125 forscanning fixture and/or reinforcement wire attachment. The abutmentfeatures 126 are specific to various systems commercially available. Thefigures show a tapered abutment mating surface 126 and female thread127.

FIGS. 53-54 show scan flag/analogs 122 attached to converted prosthesis103 with copings 112 using definitive screws 121.

FIGS. 55-56 show converted prosthesis 103 with scan flags/analogs 122mounted to fixture 130 by attaching one or more scan flags 122 to thebase with adjustable means to orient the prosthesis properly forscanning. For illustration an approximate mounting angle of 45 degreesis shown. In this example, the converted prosthesis 103 is mounted toarticulated arm 131 with screw 129 that fits into the threaded hole ofscan-flag/analog 122. Base 132 is mounted onto the base of the scanningmachine.

The provisional or duplicate prosthesis with attached scan flags/labanalogs is scanned into the design software. This process captures theaccurate position of the implant multi-unit abutment relative to thesoft tissues and it also captures the tested prosthetic contours to aidin the design of the definitive prosthesis. After the prosthesis hasbeen scanned in, a physical model may optionally be created by creatinga soft tissue moulage and pouring dental stone into the provisional orduplicate prosthetic utilizing the scan flags as the laboratory analogs.

FIG. 57 schematically shows the application of solder or brazingpreforms 133 to attach reinforcement bars 134 prior to pouring dentalstone. Preforms 133 may be inserted into holes in the scan-flag/analogsand heated to attach bars 134. Low-temperature solders, brazingcompounds, and hot-melt or other adhesives may be utilized in a preformor dispensed method to increase the rigidity of the analog assemblyprior to casting.

This method ensures a fast and efficient means of transferring allpertinent and relevant information from a converted denture required fordesigning a definitive prosthesis from digital scanning and creating themost accurate and precise physical model that can be mounted in anarticulator with the aid of a bite registration in preparation forpost-processing of the machined prosthesis, for example to verifypassivity of fit, occlusion, etc.

In addition to the screw attachment of the scan flags to the modifiedprosthesis, scan flags may be attached to the prosthesis withincorporated copings of FIG. 43 prior to the drilling operations shownin FIGS. 45-47. In this case, another embodiment of the scan flag (notshown) with a post feature equivalent to post feature 101A of separablescrew would be inserted into copings 112 of the modified prosthesis andretained by the embedded cap 102. If the separable fastener uses asnap-fit feature to retain the cap to the post, drilling may not berequired through the prosthesis to mount the scan flags or lab analogsto the prosthesis or to attach the modified prosthesis to the abutmentsafter lab use. For example, U.S. Provisional Patent Application62/774,402 describes the use of spring fingers and O-rings for separablefastening of the coping to the abutment for lift-off, and the use offilms to prevent adhesive from entering interior portions of theseparable fastener. Scan flags and lab analogs may also be engaged withtransferred copings using similar mounting features as the post used inthe transfer pick-up process. The referenced patent application alsoincludes separable systems in which the post attaches directly to thecoping without a cap which may be applied for mounting scan flags or labanalogs as variations of the methods described above. Since thedimensions of the coping and its engagement with the abutment isprecisely controlled, having snap-in scan flags engage with a cavitybetween the top of the coping and the separable cap or an internalgroove or other feature of the coping may be desirable.

Variations of using the modified prosthesis as a digital scan model, orusing the inventive concepts disclosed to create a permanent prosthesiswill be recognized as possible to dental practitioners. For example,instead of using a dual-purpose scan flag and lab analog, single purposescan flags can be mounted into the provisional prosthesis for scanning,and subsequently replaced with lab analogs prior to casting. In additionto the attachment of scan flags to a modified prosthesis fordigitization, the separable fastener may be used to transfer a copingand cap to a new impression after implant surgery. A scan flag or labanalog may be attached and held to the impression with transferredcoping for digitization or casting by substituting the new impressionfor the modified prosthesis in any of the processes above. FIG. 58describes a work-flow for using the temporary alignment fasteners with apermanent prosthesis fabricated from a digital model based on animpression.

FIGS. 59-60 show an embodiment of a simple torque-driver 113 that can beused for the temporary coping attachment process discussed in referenceto FIG. 40. Shaft assembly 135 contains a spring friction cylinderportion 141 and drive portion 138 designed to engage the temporary screw100. Spring 136 has an interference fit with cylinder 141, and thus whenspring 136 is rotated in the “unwind” direction of the spring, adesigned amount of slip torque is present between the spring andcylinder. In the “wind” direction, the spring binds on the cylinder.This provides unequal drive torque capability in the two rotationdirections. Slot 139 in drive cap 137 engages spring end 140, and snapsonto the end of the shaft assembly, thus when the cap is rotated in theclockwise direction, cylinder and drive slip at a known torque. When thecap is rotated in the counterclockwise direction, the spring binds onthe shaft to provide a higher screw removal torque before slipping.

FIG. 61 shows an embodiment of a temporary screw post extractor 115which may be used to remove post 101 after the pick-up process as shownin FIG. 44. The extractor utilizes a hollow metal tubular split-cylinderend portion 142 that deflects to grip the end of the temporary screwpost 101, allowing removal of the separable fastener posts or othertypes of fasteners. FIG. 61 illustrates a hand-operated knurled end, butother torque tool systems known in the dental industry such as 3/32″friction and latch designs may be used.

FIGS. 62-63 schematically illustrate how the position of the temporaryscrew post 10 of the first embodiment relative to the implant abutmentcan be determined. As the temporary screw is rotated clockwise, the cap11 will be pushed axially away from the screw threads of the post by thecoping. The depth of threaded engagement and the length of the temporaryscrew post 10 and cap can be designed to have the top of the post 10coincide with the top of the cap 11 as shown in FIG. 63 when thetemporary screw is properly positioned. At this point, a drive tool witha square socket cavity (not illustrated) would disengage from thetemporary screw assembly since the post 10 would no longer extend intothe tool socket cavity.

FIGS. 64-66 illustrate different embodiments of the end of the temporaryscrew post that engages the cap. FIG. 64 shows a modified version of thecylindrical post 101 designed for frictional engagement on cylindricalportion 85 with a cap having a circular bore similar to that shown inFIG. 34. In FIG. 65, the cylindrical post is slotted, and the resultingbeam portions 86 sprung open to provide additional frictional retentionof a cap through spring action with the deflecting beams. Variousfeatures such as symmetric axial splines 87 (FIG. 66), asymmetricsplines or grooves, and textures may also be used to tailor drivingtorque and axial retention force of the cap to the temporary attachmentpost. Non-symmetric features may also be utilized to tailor differentinstallation torque and extraction forces. Surface finish andcoefficients of friction of the mating materials may also be used tocontrol the driving and retention properties. Temporary attachment postsand caps may be made from metal and polymer materials such as titanium,stainless steels, nylon and PEEK and other non-corrosive biocompatiblematerials.

If additional off-axis accommodation is desired when extracting thetemporary attachment post from the coping after pick-up, someflexibility may be incorporated into the temporary attachment post, suchas the necked down portion 88 of the temporary attachment post shown inFIG. 67, which allows the temporary attachment post to flex slightlyoff-axis during the pick-up process. Under tension, the alignment of thetemporary screw axis with this necked-down portion can be designed toalign the axis of the implant abutment threads with the coping threadsbut allow some bending when the tension is released. Note that thisalignment flexibility will generally not be required during the finalscrew attachment process. The final attachment process is moreaccommodating of axial misalignment of multiple abutments than thecoping pick-up process. During pick-up, the prosthesis with copingsincorporated must be removed from all abutments simultaneously. Forfinal attachment, each definitive screw is attached individually afterthe copings of the prosthesis are positioned on the implant abutments.

FIG. 68 shows an embodiment of a temporary screw cap 94 that includesspring features 95 that engage the outer diameter 96 of the temporarypost. If desired the portion of the temporary screw cap with the springfeatures may be made of a different material than the remainder of thecap.

Although the temporary screw of FIG. 69 has a similar appearance to thatshown in FIG. 68, it has distinct functionality. FIG. 69 shows anembodiment of a temporary alignment screw 58 having threaded portion 62,breakaway flange 60 and hex drive portion 61. The flange 60 pushes downon the top of the coping as the temporary alignment screw threads 62 arerotated into the implant abutment. The flange portion may be molded ontoa temporary attachment post with threaded portion 62 and drive portion61 by insert molding if different materials are desired. Preferable, allportions of the alignment screw are molded integrally of a singlematerial. The cap and post do not slide axially relative to one another.Instead, small break-away tabs 59 in the flange portion are designed toyield under axial force during the prosthesis and coping assemblyremoval after the bonding step. The breakaway portions are designed tofracture at an axial force exceeding the force applied to align thecoping to the implant abutment for pick-up.

FIG. 67 employed a temporary alignment screw post with a waist that canbend during prosthesis removal in the pick-up process. It is alsopossible to provide additional off-axis accommodation during copingpick-up with temporary screws that do not bend. For example, in FIG. 70,a temporary alignment screw post 25 includes a rounded portion 27 thatbears against the central straight bore of cap 26. FIG. 71 shows atapered profile 29 on cap 30 which engages a straight cylindricalportion of post 28. It is preferable to prevent the incursion ofadhesive in the gaps between the post and cap that allow the post topivot. FIG. 71 includes a thin protective film 56 for this purpose. Thisfilm should be chosen to deform easily when the post is pivoted.

FIG. 72 shows a thin retaining ring 32 that engages temporary attachmentpost 31. The retaining ring 32 also provides a one-way insertiondirection of temporary attachment post 31. This preferential insertiondirection also corresponds to the relative motion of the post andretaining ring for release in the pick-up process.

FIG. 73 shows another embodiment of a temporary alignment screw thatdoes not have relative axial sliding between the post and cap. In thisembodiment a thin retainer 35 that may be comprised of a metallic orpolymer sheet is attached to the top portion of temporary attachmentpost 33 and optional cap 34. The sheet 35 may be attached to temporaryattachment post 33 using adhesives, plastic or metal welding, etc. Afterthe adhesive has cured holding the coping to the implant abutment, themechanical connection between the post and cap is overcome by axialforce in the pick-up process. The mechanical connection can be designedto fail by adhesive failure or by fracture of the joint or the sheet 35.

FIG. 74 shows another embodiment of a temporary alignment screw withoutrelative sliding between the cap portion and the post portion. In thisembodiment, a compliant or frangible portion of the post 37 is used toattach a cap 38 to the post. Under tension, the cap portion 38 holds thecoping in position against the abutment for pick-up into a prosthesis.Compliant portion 37 may be for example an elastomeric material toprovide some angular motion during prosthesis removal after the pick-upmaterial sets. The compliant portion 37 itself or one of its interfaceswith the cap or post may provide a separable interface with controlledaxial breakaway force. Other methods of separating a compliant portionmay include exposure of compliant portion 37 made from a material easilyaffected by heat, any wavelength of electromagnetic energy, or achemical reaction that may be applied externally or as part of thepick-up process.

The inventive concepts disclosed are not meant to be restricted to atemporary attachment post with standard screw threads that both engageand disengage the threads in the implant abutment through rotations. Forexample, alternate separable temporary attachment posts embodiments arepossible providing features that allow the post to removably hold thecoping to the abutment by other means than a separable cap. For example,as shown in FIG. 75 an alignment fastener 39 may contain a separablethreaded or serrated portion 40 that engages the screw threads in theabutment for pick-up, but that will release with axial force after. FIG.75 shows a temporary attachment post 39 having a slot 41 and asymmetricthreads or serrations 40 that allow the temporary attachment post to beinserted through rotation for alignment for coping pick-up but may besubsequently extracted with a separation force in the axial direction.Although the threads could be designed to provide engagement with theimplant abutment threads through axial motion in the opposite directionto the arrow shown in FIG. 75, rotation to a design torque on engagementis generally preferred. If the post 39 is designed to be pulled out ofthe abutment during the coping pick-up process, it will subsequentlyneed to be removed from flange 42 and the prosthesis assembly. Sincethere is no processing impact on patient comfort, higher mechanicalforces or a broader range of energy or chemical processing may beemployed to remove the post from the prosthesis after coping pick-up.

Further permutations of the separable alignment screw features disclosedabove are possible. FIG. 76 shows an embodiment where axial flexibilityand/or controlled retention between cap 44 and temporary attachment post43 is provided by an interface material 45 such as adhesives, silicones,and elastomeric materials contained in the space between the bore of thecap 44 and the post 43. FIG. 77 shows cap 47 retained with an O-ring 48held in grooves in the cap 47 and temporary attachment post 46. FIG. 78shows a cup-shaped interface material 57 located within the bore of thecap 44 and extending over a portion of the end of the post 43. FIG. 79shows a split-collar feature 51 on cap 50 which presses onto thetemporary attachment post 49. FIGS. 80 and 81 show alternate designs offlexure beam features in caps gripping a post. In FIG. 80, the pressureon the post 49 is reduced by pulling the cap 52 perpendicular to adiagonal of the cap as indicated by the arrows. In FIG. 81, the pressureon the post 49 is reduced by pulling in opposite directions with momentarms as shown to open the spring.

It is understood that the concept of the temporary attachment of thecoping with the abutment with an axially separable temporary post is notdependent upon having a separate cap 11 or nut 63 on the post. Ifdesired the cap or nut can be eliminated and the coping may be directlyfixed and axially separable from the temporary attachment post. That is,the coping can be designed to have an equivalent mechanical interface tothe post as the caps in the embodiments above. The mechanical interfacebetween the coping and post may be tailored to provide equivalentrotational engagement and relative axial movement above a designedminimum axial force.

Example embodiments of the coping and post being the separablecomponents include the following:

FIG. 82 shows temporary attachment post 71, engaging an interference fitof coping 72 at a position above the threaded portion. Metal,metal-reinforced, ceramic, and polymer copings, posts and fasteners maybe included in this and other embodiments. Any of the parts may havesurface treatments to control friction or adhesion.

FIG. 83 shows temporary attachment post 71 engaging integralspring-finger features 78 of coping 73.

FIG. 84 shows a temporary attachment post 71 engaging collet-type springfingers 77 of coping 74, these collet-type features may be formed usingslots in the coping 74 as shown in FIG. 84A.

FIG. 85 shows a slotted spring feature 79 formed in the temporaryattachment post 76. The spring-features engage a smaller bore portion 90of the coping 75. Such features may be of varied shapes including slots,eyelets, swaged portions, tubular swaged parts, etc. A film 56 (notshown) may be used to prevent the ingress of pick-up material into anyvoids at the top of the post/coping assembly similar to that shown inFIG. 71.

FIG. 86 shows temporary attachment post 71 and coping 75 engaged usingan O-ring or washer 80. Such washers may be elastomers, polymers,metals, etc. and may be forms in varied shapes, such as the u-shapedretainer 81 of FIG. 87.

FIG. 88 shows temporary attachment post 71 retained to coping 75 using asheet cap 82. Sheet cap 82 may be a tape, or other polymers or metalsjoined using adhesives, thermal and ultrasonic bonding, welding, andbrazing, etc. This is similar to the embodiment shown in FIG. 73, exceptthe sheet cap 82 does not have thicker cap element 34.

FIG. 89 shows temporary attachment post 71 retained using a fillermaterial 83 in the counterbore of coping 75. Fillers may include avariety of polymer adhesives or fillers, such as silicones, acrylics,epoxies, and/or soft metallic materials. Since the coping 75 in thisembodiment is fixed to the post 71, the mating surfaces of the coping 75and implant abutment must allow relative rotational motion until thepredetermined torque is achieved.

Installation of these embodiments may also be accomplished with simplepolymer or metal tools 84, for example, as shown in FIG. 90 that engagethe flats or other features of the coping 75, and/or of features on topof the threaded post 71.

Although the descriptions above use rotational engagement of the bottomof the post with internal threads of the abutment as a preferredapproach, this is not meant to be limiting. Alternate approaches forengaging a temporary attachment post with abutment threads through axialinsertion without rotation are considered to be part of this disclosure.For example, the split post bottom structure shown in FIG. 75 whichallows axial extraction can also be used for axial insertion. Similarly,an interference fit between the bottom of the post with the threads mayalso be designed to provide sufficient engagement to provide adequatealignment and fixing of the coping for the pick-up bonding processdescribed earlier. For non-rotary extraction of the post, it is notnecessary to have the extraction force of the post-abutment threadinterface greater than the force required for relative movement of thecoping or cap with the upper end of the post. That is, if the temporaryattachment post remains fixed to the coping during the pick-up step, thepost can be removed from the dental appliance after removal from thepatient's mouth.

Although axially symmetric interfaces between coping and abutment havebeen described for most embodiments, the inventive concepts may also beapplied to asymmetric abutments and copings as long as the copingdoesn't need to rotate on the implant abutment as noted, for example,with the embodiment of FIG. 89.

Various embodiments have been described to illustrate the disclosedinventive concepts, not to limit the invention. Combining inventiveelements of one or more of the embodiments with known materials,components and techniques in dental science to create furtherembodiments using the inventive concepts is considered to be part ofthis disclosure.

Any of the embodiments may contain a film or deposited material on topof the cap and temporary attachment post to prevent adhesion to thetemporary attachment post of materials used for pick-up, as shown in thefilm 56 of FIG. 71.

Temporary attachment posts may be rotationally driven into the abutmentthreads using either the cap, coping or the temporary attachment postitself. Temporary attachment posts and caps may have varied drivefeatures such as male or female knurls, hex, spines, spannernotches/holes. These design alternatives are driven by functionalrequirements of a particular implementation.

Other means of attaching/joining a secondary separable portion includeinsert-molding, use of adhesives, waxes, solders or other metallicmaterials, heat-staking, and ultrasonic bonding.

Break-away portions may also be formed by two-shot molding, dispensingor otherwise placing a secondary mechanically, thermally, orelectromagnetically fusible material on a portion of the fastener toprovide the break-away function.

Thin-film or thick-film metallic and polymer coatings may be applied toportions of the fastener to tailor friction and insertion and extractionforces, enhance adhesion of pick-up materials, and other properties suchas corrosion-resistance.

What is claimed is:
 1. A dental system for temporary attachment of acoping to a threaded implant abutment comprising: a coping; and animplant abutment having threads; and a separable screw having an axiswith a length measured along the axis and a width measured perpendicularto the axis, the separable screw comprising: a post having an axis, afirst post end and a second post end, wherein the first post end isthreaded to mate with the implant abutment threads; and a cap having anaxis, a first cap end and a second cap end, wherein the cap has an axialbore at the first cap end sized to receive the second post end throughan insertion length; and wherein the second post end is mechanicallyattached inside the bore of the cap; and wherein the mechanicalattachment is configured to prevent relative rotary movement between thepost and cap below a predetermined screw engagement torque and to allowrelative axial movement between the post and cap above a predeterminedaxial separation force.
 2. The system of claim 1 wherein the axialseparation force is applied through a pick-up process in which thecoping is adhered to a separable dental element.
 3. The system of claim2 wherein the first end of the post remains attached to the implantabutment after the pick-up process.
 4. The system of claim 1 wherein thecap is attached to the post with at least one of a mechanicalinterference or adhesive.
 5. The system of claim 1 wherein the axialseparation force is less than about 5 pounds.
 6. The system of claim 1wherein the coping has an aperture sized to allow the post to extendthrough the aperture and to allow the cap to hold the coping onto theimplant abutment.
 7. The system of claim 1 wherein the cap does notrotate on the post when a torque of less than about 1.6 inch-ounces isapplied to the cap.
 8. The system of claim 1 further comprising one ormore drills sized to provide clearance in a separable dental element fora definitive screw.
 9. The system of claim 1 further comprising aprosthesis having a cavity sized for coping pick-up processing forscrew-attachment to the implant abutment.
 10. The system of claim 1further comprising at least one scan flag.
 11. The dental system fortemporary attachment of a coping to a threaded implant abutment of claim1 wherein the post is comprised of metal and the cap is comprised of apolymeric material.
 12. The dental system for temporary attachment of acoping to a threaded implant abutment of claim 1 wherein the second postend includes a region within the insertion length having a width that isless than the width of the threaded portion at the first post end. 13.The dental system for temporary attachment of a coping to a threadedimplant abutment of claim 1 wherein the cap is shaped to engage a torquedriver.
 14. The dental system for temporary attachment of a coping to athreaded implant abutment of claim 1 wherein the length of the separablescrew is less than about twice the width of the cap.
 15. The dentalsystem for temporary attachment of a coping to a threaded implantabutment of claim 1 wherein a portion of the post between the secondpost end and the threaded section or a portion of the cap from the firstcap end through the insertion length of the post includes anon-cylindrical surface profile.